The present invention relates to a heat exchanger in which two media having different temperatures are conducted in separate cycles. As a rule, the cycle in which the warmer medium is conducted is called the primary cycle, and the cycle in which the cooler medium is conducted is called the secondary cycle.
In order to achieve a high efficiency of a heat exchanger, the boundary area separating the two media should be as thin as possible, have a largest possible surface area and a good thermal conductivity. Additionally, the efficiency can further be improved by the media flowing in opposite directions to each other.
A heat exchanger having a tube arrangement for the heat-absorbing medium and an outer jacket for the heat-dissipating medium has already been proposed wherein the tube arrangement encompasses very thin tubes of intertwined layout, thereby comprising a very large surface area. However, such appliances are relatively unsuitable when the medium flowing through the tube arrangement carries particles, such as lime, which can be deposited on the tube walls. This leads to a gradual clogging of the tube arrangement which can hardly be rectified mechanically. Moreover, the constructional effort required for the intertwined tubes is considerable.